Silverline sr 12 & sr 11

What differences can one expect between the speakers? I use a vintage NAD 7175pe receiver and generally listen to blues,rock,folk at moderate levels. I presently have Silverline sr 12's but I wonder about the sr 11's for a 12X14 office. Thank you.
I have owned the SR-15s and SR-11s (twice). Why twice? The SR-11s were first and I liked them. Thought the 15s would be an upgrade but they weren't IMO. It had more to do with the presentation than tone. The 11s have a more natural, musically involving presentation.
Never heard the SR-12s.